Sofa



FIG. 1 is a front view of a sofa showing my new design;

FIG. 2 is a top view thereof;

FIG. 3 is a right view thereof;

FIG. 4 is a left side view thereof; and,

FIG. 5 is a rear view thereof.

The structural elements in the figures depicted by means of broken lines have been shown for the purposes of illustrating portions of the sofa which form no part of the claimed design. 

CLAIM The ornamental design for a sofa, as shown and described. 